The invention relates to a method for producing a drill assistance device in order to precisely place a pilot hole for a tooth implant, wherein the pilot hole for the tooth implant is aligned relative to the teeth that still remain in the jaw.
WO 99/32045 discloses a method for producing a dental drill assistance device for tooth implants. In accordance with such method, a three-dimensional computer image is modeled using an image of the jaw relative to an imprint surface. With the computer graphics generated in this manner at least one bore hole position is determined, with the bore hole position being specified in three dimensions, including the bore hole end point and the bore hole length in relation to the jaw imprint. Subsequently, at least one set of implant bore hole coordinates is fed into a computer-controlled precision machine tool. Envisioned on a drill body is a first surface which corresponds with the imprint surface of the jaw. Using the precision machine tool, a drill guide base is prepared inside the drill body for each of the previously entered sets of bore hole coordinates with the corresponding bore hole position and bore hole orientation previously determined using the section of the jaw.
According to this known method the position and the orientation of the bore hole are determined by way of an imprint that is taken from the jaw bone. When placing tooth implants the shape and the size of the implant is exactly planned using x-ray pictures. The implant position in the jaw is predetermined with as much precision as possible. In use are drill templates which are intended to allow the placement of an exactly positioned bore hole. Ordinarily it is difficult, however, to determine the position of a pilot hole exactly during the drilling process because the information that is contained in the x-ray cannot be exactly transferred to the optical images which the physician sees while drilling. The physician relies on experience, in particular with respect to the position and the path of the nerve tracts that run along the jaw bone. Thus, we have the unsatisfactory result that, on the one hand, the implants are planned and manufactured very exactly and precise to the last detail but, on the other hand, their positioning in the jaw area has been effected to date on the basis of individual experience, which can vary considerably among different dentists.
A method and an apparatus for the localization of tooth implants and a device for the allocation of coordinates became known in the art from German published patent application 197 25 197. This method and apparatus for the localization of tooth implants process metrologically collected anatomical data reflecting the nature of the jaw bone of the respective patient. Based on the stored data sectional drawing information is generated which is used to define the implant location. Using an allocated reference system of coordinates, the actual bone geometry, the metrological information, the design of a plaster model of the jaw and the geometry of an operational assistant template can be placed in relation to one another with such a level of precision that a highly accurate placement of a bore hole in the jaw bone, which will receive the tooth implant, is supported. The transfer of the respective coordinate information to the assistance devices and processing installations that are in use is supported by a mechanical transfer element, which can, for instance, have an arc-shaped design containing an adapter that can be introduced into the mouth of the patient.
Other processes for implant bore holes in the jaw are known from U.S. Pat. No. 5,888,065 which forego a precise determination of the pilot hole position altogether.